Petroleum-based materials are integral to the world's economy and demand for such fuels and consumer products is increasing. As the demand rises, there is a need to efficiently and economically extract petroleum-based materials to fulfill that demand. As such, it would be advantageous to not only be able to extract petroleum-based materials from the earth, but to also recycle consumer products to recapture those petroleum-based materials.
Worldwide oil consumption is estimated at seventy-three million barrels per day and growing. Thus, there is a need for sufficient oil supplies. Tar sands, oil sands, oil shales, oil cuttings, and slurry oil contain large quantities of oil, however, extraction of oil from these materials is costly and time-consuming and generally does not yield sufficient quantities of usable oil.
Soil contaminated with petroleum products is an environmental hazard, yet decontamination of petroleum-tainted soil is time-consuming and expensive.
Furthermore, it has been estimated that 280 million gallons of oil-based products such as plastics go into landfills each day in the United States. It would be desirable to recapture and recycle the raw materials of these products.
Scrap vehicle tires are a significant problem worldwide and their disposal presents significant environmental and safety hazards, including fires, overflowing landfills, and atmospheric pollution. While there are a number of existing applications for these tires, including tire-derived fuels, road construction, and rubber products, these applications are insufficient to dispose of all the available scrap tires. The major components of tires are steel, carbon black, and hydrocarbon gases and oils, which are commercially desirable. As such, it is advantageous to develop processes for the recovery of these products from scrap vehicles tires. Prior art methods of decomposing scrap vehicle tires do not produce commercial-grade carbon black and require high temperatures and extended exposure times for recovery of the hydrocarbon components.
Efforts to recycle tires using microwave technology has been described in U.S. Pat. Nos. 5,507,927 and 5,877,395 to Emery. Efforts to recover petroleum from petroleum-impregnated media has been described in U.S. Pat. Nos. 4,817,711 and 4,912,971 to Jeambey. Efforts to decompose plastics using microwave radiation has been described in U.S. Pat. No. 5,084,140 to Holland. The prior work has involved the use of single-frequency microwave radiation. Single-frequency microwave radiation is a slow process that does not provide uniform heating. Moreover, single-frequency microwave radiation typically results in arcing on metal components.
Thus, there is a need for methods and apparatuses for the recycling of petroleum-based compositions and for the recovery of petroleum-based materials from composites containing petroleum-based materials. The invention is directed to these and other important needs.